Devices permitting the sequential display of a plurality of coded images by relative movement of an image member relative to a shutter member have been known for many years. The image member has a plurality of interposed coded images disposed thereon while the shutter member has a plurality of shutter elements disposed thereon that are separated by a plurality of viewing elements. The shutter elements perform the dual functions of selectively blocking from view all but one of the interposed coded images while bridging the gaps between the coded strips that form what can be termed an active image. With this, the plurality of shutter elements decode the active image of the plurality of coded images, and the active image appears to be a complete, coherent image.
When the image member and the shutter member undergo relative movement by a predetermined amount, the strips of the previously active image are concealed and the next succeeding coded image assumes the fleeting position as an active image. This procedure will continue through a cycle of all coded images that are disposed on the image member. Once the cycle is complete, the first coded image will again appear to start a new, identical cycle. The number of unique coded images is mathematically limited by the width of the shutter element relative to the width of the strips that form the coded images. Stated more particularly, the number of coded images cannot exceed one plus the result of the width of each shutter element divided by the width of each coded image strip.
As one knowledgeable in the art will appreciate, the ability of a display device to display images with clarity and resolution is dependent not only on the number of discrete images that can be displayed but also on the ability of the device to obtain precise registration and alignment between the coded images and the shutter elements and to maintain that precise registration during relative movement within the device. Just as critical to the performance of such display devices is the ability of the device to induce and maintain close contact between the shutter elements and the coded images over their entire display surfaces.
Lack of complete contact between the shutter elements and the coded images creates thin air pockets between the layers thereby creating undesirable shadows that diminish the observer's ability to perceive the display image. Incomplete contact also results in an undesirable parallax viewing conflict where multiple images can be perceived due to the ability of the observer to see around and, therefore, behind the shutter elements.
Where complete contact between the shutter elements and the coded images can not be achieved, the intended animation effect will be frustrated and, additionally or alternatively, the designer will be forced to compensate by implementing a design with sufficiently few animation phases to eliminate the viewing conflicts and other resulting disadvantages. Conversely, where better contact can be achieved, more phases of animation are possible thereby enabling more advanced and intricate animation sequences.
The prior art has employed numerous arrangements including corrective spring-loaded pressure plates, bent tab systems, and similarly complex arrangements in seeking to achieve and maintain precise alignment and consistently close contact between shutter element and coded image layers. Such arrangements have worked to some degree of success but have proven to be bulky, expensive, complex in structure and function, and often unreliable. These and further factors have limited and even entirely prevented the ability of such devices to achieve widespread market success including relative to the advertising, direct mail, greeting card, book, magazine, packaging, and other markets.
The present inventor advanced this art with, among other things, the disclosure provided by his U.S. Pat. No. 5,901,484 for a Manually-Operated Moveable Display Device and his U.S. Pat. No. 6,286,873 for a Visual Display Device With Continuous Animation, each being incorporated herein by reference. The '484 patent presented solutions to many of the deficiencies of the prior art with its disclosure of an arrangement with inner and outer cylinders having coded images and shutter elements imprinted thereon and with creases formed in the cylinders such that the cylinders themselves exert a contact pressure therebetween by virtue of their being formed from a resilient material. Such arrangements have represented advantageous improvements due their simplicity and effectiveness and their ability to be employed in markets that have been inaccessible to the prior art.
Nonetheless, it has become clear that there remains a need for new moveable display device constructions that are still flatter and more compact to enable, among other things, their use in applications where moveable display devices previously could not be applied. Of course, it would also be an advantageous improvement to provide moveable display devices that are simple and inexpensive in structure and function while being able to achieve and maintain accurate alignment and close contact between a shutter element layer and a coded image layer.